Generally, an underwater pipeline is laid in the bed of the body of water and buried in the bed of the body of water at a certain depth, in particular at landings and in shallow water to protect the pipeline from external agents. Once the pipeline has been buried, it is necessary to check if the position of the pipeline in the bed of the body of water falls within the design values. Another parameter to check is the trenching height, which by convention is the distance between the upper end of the pipeline and the upper end of the bed of the body of water.
U.S. Pat. No. 5,537,366 discloses a sonar system, which is able to detect cable and pipelines buried under the bottom of the body of water while distinguishing them from a rock stratum.
Y R Petilot Et Al.: “Real time AUV pipeline detection and tracking using side scan sonar and multi-beam Echosounder”, Ocean'02 MTS, vol. 1 (ISBN: 0780375343) discloses a technique for reliably detecting and tracking pipelines using multi-beam echo-sounder and side-scan sonar system.
U.S. Published Patent Application No. 20140165898 discloses an unmanned underwater vehicle for localizing and examining an object arranged at the bottom of a body of a water.